2. Index
Introduction
Applicability Statement
Protocol overview
Operation mode
Service Advertisements
Format of SLP
Additional feature
Summary
5/7/2015Raj Hirani (130040131024)
2
3. As computer become more portable and network larger and more
pervasive, the need to automate the location and client configuration for
network services also increases.
The Service Location Protocol is an IETF(Internet Engineering Task Force)
standard that provides a scalable framework for automatic resource
discovery on IP networks
5/7/2015Raj Hirani (130040131024)
3
4. Introduction
The Service Location Protocol (SLP) provides a flexible and scalable
framework for providing hosts with access to information about the
existence, location, and configuration of networked services.
SLP provide dynamic configuration mechanism for application in LAN.
Application are modeled as clients that need to find servers attached to
any of the available networks within an enterprise.
5/7/2015Raj Hirani (130040131024)
4
5. Protocol Overview
SLP establishes framework for resource discovery that includes three ”
agents ” that operate on behalf of the network-based software:
User Agents(UA) perform service discovery on behalf of client software.
Service Agents (SA) advertise the location and attribute on behalf of services.
Directory Agents (DA) aggregate service information into what is initially a
stateless repository
5/7/2015Raj Hirani (130040131024)
5
7. These fig. shows the two different method for DA discovery
Active
UA and SA multicast SLP request to network
Passive
DA multicast advertisements for their service and continue to do this periodically in case any UA or
SA have failed to receive the initial advertisement
5/7/2015Raj Hirani (130040131024)
7
8. Operation mode
SLP has a two mode
When DA is present, it collects all service information advertised by SA and
UA unicast their requests to the DA
In the absence of a DA, UAs repeatedly multi-cast the same request they
would have unicast to a DA. SAs listen for these multicast requests and
unicast responses to the UA if it has advertised the requested service.
When a DA is present, UAs receive faster responses, SLP uses less network
bandwidth, and fewer (or zero) multicast messages are issued.
5/7/2015Raj Hirani (130040131024)
8
9. Service Advertisements
Services are advertised using a Service URL, which contains the service’s
location: the IP address, port number and, depending on the service type,
path. Client applications that obtain this URL have all the information they
need to connect to the advertised service. The actual protocol the client
uses to communicate with the service is independent of SLP.
5/7/2015Raj Hirani (130040131024)
9
13. ADDITIONAL FEATURES
The essential function of SLP is service discovery. SLP has also been
designed to provide security, extensibility, support for browsing operations,
and operation over IPv6. These features extend the utility of SLP, and will be
especially useful once a standardized security infrastructure has been
widely adopted on IP networks.
5/7/2015Raj Hirani (130040131024)
13
14. Security
SLP is designed to make service information avail-able, and it contains no
mechanisms to restrict access to this information. Its only security property is
authentication of the source of information, which prevents SLP from being
used to maliciously propagate false information about the location of
services.
5/7/2015Raj Hirani (130040131024)
14
15. Digital signatures
An SA can include a digital sig-nature produced with public key
cryptography along with its registration messages. A DA can then verify the
signature before registering or deregistering any service information on the
SA’s behalf. These digital signatures are then forward-ed in reply messages
to UAs, so they can reject unsigned or incorrectly signed service
information. Of course, DAs and UAs can only verify signa-tures, not
produce them.
5/7/2015Raj Hirani (130040131024)
15
16. SUMMARY
SLP is an IETF standard for service discovery and automatic configuration of
clients. It provides for fully decentralized operation and scales from a small,
un administered network to an enterprise network where policy may
dictate who should dis-cover which resources. This paper describes how SLP
operates and how it adapts to conditions where infrastructure is not
available, where administration is minimized, and where network
administrators in large enterprises wish to reduce tedium and workload.
While alternative mechanisms exist, SLP remains the most general and
versatile solution for service discovery on TCP/IP networks
5/7/2015Raj Hirani (130040131024)
16
17. Reference
J. Veizades, E. Guttman, and C. Perkins, “Service Location Protocol,” IETF,
RFC 2165, June 1997; available at http://www.rfc-editor.org/rfc/rfc2165.txt .
E. Guttman, C. Perkins, J. Veizades, and M. Day, “Service Location Protocol,
Version 2,” IETF, RFC 2608, June 1999; available at http://www.rfc-
editor.org/rfc/rfc2608.txt .
R. Droms, “Dynamic Host Configuration Protocol,” IETF, RFC 2131, Mar. 1997;
available at http://www.rfc-editor.org/rfc/rfc2131.txt .
C. Perkins and E. Guttman, “DHCP Options for Service Location Protocol,”
IETF, RFC 2610, June 1999; available at http://www.rfc-
editor.org/rfc/rfc2610.txt .
5/7/2015Raj Hirani (130040131024)
17
18. “
”
Thank You
Any Question ?
If opportunity doesn’t knock, build a door .
- Milton Berle
5/7/2015Raj Hirani (130040131024)
18
